Field of the Invention
The invention relates to a control device for final control elements of an internal combustion engine, a control unit for actuator drives of an internal combustion engine, and a method for controlling an internal combustion engine.
Prior art control devices for final control elements of internal combustion engines generate, inter alia, control signals for controlling final control elements and control commands for actuating actuator drives, the control signals and control commands for controlling final control elements being dependent on at least one measured variable such as an accelerator pedal value or the rotational speed.
The final control elements can be driven by actuator drives. For the actuator drives, to a certain extent control units are provided that generate actuating signals for the actuator drives of the internal combustion engine as a function of the control commands of the control device. Both the control device and the control unit have one communications interface each, to which a bus, for example, the CAN bus, can be connected. The control device can then transmit the control commands through the interface and the bus to the control unit that then carries out the corresponding control functions. Such control commands may, for example, include the crankshaft angle at which charge cycle valves are to be opened or closed.
U.S. Pat. No. 5,201,296 to Wunning et al. discloses an internal combustion engine in which the valves and injection processes are controlled as a function of a signal of a crankshaft angle sensor such that control processes are triggered as a function of the position of the crankshaft.
The prior art includes transmitting the control commands segment-synchronously onto the bus. A segment is defined by the distance between two successive dead center points of the pistons of two cylinders that directly follow one another in the ignition sequence. Here, the control command contains setpoint crankshaft angles that are each related to the top dead center during the ignition of the respective cylinder. The control commands are, therefore, always related to the respective crankshaft angles. Such a relationship has the disadvantage that the reference base for the crankshaft angle of each cylinder is different and depends on the number of clock cycles of the working cycle. In addition, control commands can also be transmitted only for the time horizon of a working cycle because, beyond it, the crankshaft angle is no longer unambiguous.
It is accordingly an object of the invention to provide a control device for final control elements of an internal combustion engine, a control unit for actuator drives of an internal combustion engine, and a method for controlling an internal combustion engine that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices and methods of this general type and that ensures easy operation of the internal combustion engine in different operating modes with unchanged control commands.
With the foregoing and other objects in view, there is provided, in accordance with the invention, a control device for final control elements of an internal combustion engine having sensors sensing at least one measured variable, an incremental crankshaft angle sensor having an increment number and supplying a measurement signal having pulses, final control elements, actuator drives connected to the final control elements, and a control unit having a synchronizer for synchronizing counters and a control unit counter with a counter reading, the control unit at least in part driving the final control elements with the actuator drives, the control device including a control command generator connected to the actuator drives and controlling the actuator drives as a function of the at least one measured variable, the generator generating control commands with setpoint counter readings for execution of control functions of the engine, a communications interface for exchanging messages with the control unit, the interface connecting the control command generator to the control unit, a revolving counter independent of the control unit counter and having a counter reading dependent upon parameters including the pulses of the measurement signal of the crankshaft angle sensor and independent from the increment number of the crankshaft angle sensor during a working cycle of the engine, the counter reading of the revolving counter and the counter reading of the control unit counter synchronized through the synchronizer of the control unit, and the counter reading of the control unit counter being dependent upon the parameters.
The invention is characterized by the fact that the internal combustion engine can be operated in different operating modes, such as two stroke, four stroke, six stroke, or eight stroke, without the control commands having to be changed.
In accordance with another feature of the invention, the revolving counter is a dual counter with a predefined bit length.
In accordance with a further feature of the invention, the counter reading of the revolving counter interpolates between the pulses of the measurement signal.
In accordance with an added feature of the invention, the final control elements are gas exchange valves.
With the objects of the invention in view, there is also provided a control unit for actuator drives of an internal combustion engine having a control device generating control commands for controlling the actuator drives, the control commands containing setpoint counter readings for execution of engine control functions, a communications interface for exchanging data with the control device, an incremental crankshaft angle sensor having an increment number and generating a measurement signal having pulses, and a counter with a first counter reading, the control unit including a revolving counter independent from the counter and having a second counter reading dependent upon parameters including the pulses of the measurement signal and independent of the increment number of the crankshaft angle sensor during a working cycle of the engine, a controller executing the engine control functions as a function of the second counter reading and the setpoint counter readings, a synchronizer for synchronizing the second counter reading and the first counter reading, and the first counter reading being dependent upon the parameters.
In accordance with an additional feature of the invention, the second counter reading interpolates between the pulses of the measurement signal.
In accordance with yet another feature of the invention, the actuator drives are drives for charge cycle valves.
With the objects of the invention in view, there is also provided a method for controlling an internal combustion engine having actuator drives, including the steps of generating control commands for controlling the actuator drives as a function of at least one measured variable in a control device, the control commands containing setpoint counter readings for an execution of engine control functions, transmitting the control commands to a control unit for the actuator drives, changing a counter reading of a first counter as a function of pulses of a measurement signal from an incremental crankshaft angle sensor having an increment number, the first counter being a revolving counter with a maximum counter reading independent of the increment number of the crankshaft angle sensor during a working cycle of the engine, and executing, in the control unit, the engine control functions predefined by the control commands as a function of the counter reading of the first counter, the setpoint counter readings, and a counter reading of a second counter independent of the first counter.
Other features that are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a control device for final control elements of an internal combustion engine, control unit for actuator drives of an internal combustion engine, and a method for controlling an internal combustion engine, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.